Researchers at Tufts University have made the world's smallest electric motor, which is no bigger than a single molecule.
According to the Guinness World Records, the smallest electrical motor on the planet is 200 nanometers. But now the new microscopic motor will replace it as the tiny motor is just one nanometer across, about 60,000 times smaller than the width of a human hair.
The low temperature scanning and tunneling microscope at Tufts University, one of only about 100 in the United States, was instrumental in the development of the microscopic motor. The new class of device could be used in applications ranging from medicine to engineering.
The research team published a paper detailing the new electric motor in Nature Nanotechnology on Sunday.
The excitement is in the demonstration that you can provide electricity to a single molecule and get it to do something that's not just random, Charles Sykes, senior study author and associate professor of chemistry at Tufts, said in a university press release.
Sykes said single-molecule motors are not new, but until now they've been driven by either chemicals or light. But this is the first time that electrically-driven molecular motors have been demonstrated despite a few theoretical proposals and it has significant advantages over those other technologies.
Sykes explains difficulties to power molecular motors with chemicals and light.
With the help of scanning tunneling microscope, Sykes and his colleagues were able to land on a single molecule and then measure it and spin it. They used the metal tip of the microscope to provide an electrical charge to a butyl methyl sulfide molecule that had been placed on a copper surface.
This molecule has carbon and hydrogen atoms radiating from it to form what look like two arms, with four carbons on one side and one on the other. These carbon chains were free to rotate around the sulphur-copper bond at speeds of up to 120 rpm.
Scientists found that a freezing minus 268 degrees centigrade proved ideal for tracking the motor's motion as direction and speed were affected by temperature. At higher temperatures, the motor spins much faster, making it difficult to measure and control the rotation. To achieve practical applications, breakthroughs will need to be made in the operating temperatures.
That's because as temperatures rise, the motor spins much faster, far beyond the ability of the scientists to measure the rotations. At 100K, a molecular motor spins more than a million times per second, said Sykes.
It's not that we couldn't work at a higher temperature-it's just that too much is happening. At that speed, it's just a blur, added Sykes.
Sykes said by modifying the molecule slightly, the molecular electric motors could be used to generate microwave radiation or to couple into what are known as nano-electromechanical systems (NEMS).
The next thing to do is to get the thing to do work that we can measure - to couple it to other molecules, lining them up next to one another so they're like miniature cog-wheels, and then watch the rotation propagation down the chain, BBC quoted Sykes as saying.